Nomogram Predicting Progression-Free Survival in Locally Advanced Papillary Thyroid Cancer with Recurrent Laryngeal Nerve Invasion.

Objectives: The recurrence rate of T4a papillary thyroid cancer (PTC) is relatively high, but research on the prognosis of T4a PTC is rarely investigated. This study aims to analyze the prognosis of T4a PTC patients with recurrent laryngeal nerve (RLN) invasion.

Methods: Univariable and multivariable Cox proportional hazard models were employed to identify prognostic factors for the progression-free-survival (PFS) of PTC patients. A nomogram was constructed based on essential prognostic factors to predict the risk of disease progression in T4a PTC patients with RLN invasion.

Results: A total of 418/602 (69.4%) T4a PTC patients with RLN invasion underwent surgery, the 5-year PFS rate was 89.8%. The multivariable analyses showed that age ≥55 years, preoperative vocal cord paralysis (VCP), microvascular invasion, and the number of cervical lymph node metastases (CLNM) >10 were prognostic risk factors of PFS in T4a PTC patients with RLN invasion. Our nomogram provided good discrimination, with a C-index of 0.778 in the training set and 0.793 in the validation set. No statistical difference (P = .918) was found between PFS and the surgical methods of RLN. By following up on the patient's voice condition, the RLN function was restored in approximately 82.7% of patients after RLN separation.

Conclusion: T4a PTC patients with RLN invasion are prone to disease progression under the following conditions: age ≥55 years old, preoperative VCP, microvascular invasion, and CLNM >10. The RLN nerve preservation surgery does not increase the risk of disease progression.